Categories: Power Amplifier

60 / 120 watts Power Amplifier LM4780

Operating power amplifier integrated circuit LM4780 from National Semiconductor .
What is special? Well, first of all – it is very low harmonic distortion. Typically, manufacturers indicate the maximum power of its regular genius crafts at THD 10%. At the same chip, the CG at the maximum specified power is only 0.5%!

IC Features :

Supply voltage	: 20 … 84V
Supply current absence of a signal	: 110mA
Output Power (CG = 0.5% = 35V Upit)	: 60W
Harmonic (Pout = 30W, RL = 8Ohm)	: 0.03%
S / N ratio (weighted)	: 114%

In the chip implements two identical channels of amplification and specifications are for the stereo mode of the amplifier. Chip can also operate in mono – in bridged mode. In this case, the output power at CG = 0.5% at 120 watts. The other characteristics remain practically unchanged.
Below is a schematic of the LM4780 Mono channel mode :

Parts list :

Notation on the chart	Nominal
C1	15
C2	15
C3	1uF
C4	1uF
C5	68uF/50V
C6	68uF/50V
C7	0.1
C8	10uF/50V
C9	0.1
C10	1000uF/50V
C11	10uF/50V
C12	1000uF/50V
C13	0.1
C14	0.1

R1	10K
R2	1K
R3	1K
R4	15kOm
R5	1K
R6	15kOm
R7	1K
R8	20kOm
R9	2.7 Ohm
R10	2.7 Ohm
R11	20kOm

DA1	LM4780